Effect of sintering temperature on phase transitions, properties and temperature stability of (K0.465Na0.465Li0.07)(Nb0.95Sb0.05)O3 lead-free piezoelectric ceramics

Effect of sintering temperature on (K0.465Na0.465Li0.07)(Nb0.95Sb0.05)O3 lead-free ceramics was systematically studied. The porosity inside the grains was observed, which acts as a pinning effect and leads to the increase of coercive field. Both high and low sintering temperatures (Ts) would lead to the formation of secondary phases, and the transition temperatures were modified by controlling the amount of secondary phases. At appropriate Ts, the piezoelectric activity was greatly improved with orthorhombic–tetragonal transition temperature (TO-T) near room temperature and low porosity in the grains. Effect of Ts on temperature stability (TS) was also studied, and no definite relationship between TS and TO-T is observed. The (K0.465Na0.465Li0.07)(Nb0.95Sb0.05)O3 ceramics with Ts = 1030 °C possess enhanced piezoelectric properties together with good temperature stability.